1. Field of the Invention
The present invention relates to an electronic appliance, and more particularly to an electronic appliance having two casings coupled together by a coupling.
2. Description of the Prior Art
In electronic appliances directed to mobile data processing, such as PDAs (personal digital assistants), the compactness of the appliances themselves counts most. Accordingly, in such appliances, compactness is achieved by providing operated members such as a jog dial and key tops, for example, around a display screen or on side faces of the appliances so that operations such as selection of or decision on a choice or message displayed on the screen (such operations will hereinafter be referred to also as “selection/decision operations”) are performed by use of those operated members.
On the other hand, in recent years, it has been becoming increasingly common not only to receive data but to transmit data by use of mobile data processing appliances. In conventional appliances, input of characters is achieved either by selecting and inputting one character after another by selection/determination operations as mentioned above or by inputting characters via a display screen having a transparent touch panel fitted thereto by use of a pen. In either way, it takes time and trouble to input characters. Characters can easily be input by use of a keyboard, but, where appliances need to be compact, it is not possible to secure on a surface of the appliances an ample area to provide a keyboard in. This inevitably results in small keys and a narrow key-to-key pitch, and thus makes it difficult for the user to input characters by use of those keys.
To overcome this problem, Japanese Patent Application Laid-Open No. 2001-268613 proposes building a data processing appliance with an upper half portion and a lower half portion so that, when input is performed by use of a keyboard portion, the upper and lower half portions are unfolded and, when input is performed by selection/determination operations, the upper and lower half portions are folded together.
In general, where input is performed by use of a keyboard, an appliance that is laterally elongate is preferable from the viewpoints of key arrangement and ease of input. Moreover, in general, the screen on which the input characters and symbols are displayed is easier to view when it is laterally elongate. By contrast, where input is performed by selection/determination operations, since such operations are performed with an appliance held in one hand, an appliance that is longitudinally elongate is preferable because it is then easier to hold on a palm and use.
However, the structure proposed in the aforementioned patent publication does not permit the appliance to be used from different directions. Thus, when the appliance is used in the laterally elongate orientation, it is easy to use the keyboard, but it is difficult to perform selection/determination operations. By contrast, when the appliance is used in the longitudinally elongate orientation, it is easy to perform selection/determination operations, but it is difficult to use the keyboard.
In an appliance as described above that has a foldable and rotatable screen display portion, one way to electrically connect the main portion to the screen display portion is to use leads. When leads are used, they are typically laid through a hollow shaft. With this wiring method, however, as the number of leads increases, the shaft needs to be made thicker. This, disadvantageously, makes the hinge mechanism as a whole unduly large.
Another way to electrically connect the main portion to the screen display portion is to use an FPC (flexible printed circuit) board. An FPC board is thin even when it has several tens of conductors, and thus its use helps make the hinge mechanism compact. On the other hand, an FPC board is made so long as to permit the folding and rotating movement of the screen display portion, and therefore, for example when the screen display portion is folded over the main portion, the margin portion of the FPC board becomes loose. When the FPC board becomes loose, it is prone to deteriorate by making frequent contact with members provided around. Moreover, to prevent the FPC board from popping out, it is necessary to secure inside an appliance a space to accommodate the loose portion of the FPC board. This makes difficult to make the appliance compact.
To overcome this inconvenience, for example, Japanese Patent Application Laid-Open No. H10-290084 discloses a technique whereby a plurality of FPC boards having different lengths are laid on one another and are wound around a hinge shaft. This helps eliminate the looseness resulting from the differences in inner diameter between the individual FPC boards when they are wound around the hinge shaft. This technique is based on the technique of winding an FPC board around a hinge shaft, which technique is effective in eliminating the looseness of the FPC board that occurs as the screen display portion is rotated.
According to the technique disclosed in the aforementioned patent publication, however, an FPC board is wound around a rotation shaft (24) but not around a folding shaft (not illustrated). In a video camera apparatus or the like, where the screen display portion can only be unfolded to 90° relative to the main portion as illustrated in the aforementioned patent publication, even if an FPC board is not wound around the folding shaft, the looseness of the FPC board when the screen display portion is folded over the main portion is considered to be negligibly small. However, in a case where the screen display portion is unfolded to, for example, over 180°, how to deal with the looseness of an FPC board when the screen display portion is folded poses a serious problem.